Gem Micromatic Clog Pruf

So my girlfriend's father gave me a Clog Pruf for my birthday.

I spent some time polishing it and generally making it look pretty while I waited for an order of SE blades to arrive.

Got them yesterday, popped a blade in, and noticed it doesn't secure the blade well at all. Bad enough that I shook it around and the blade started to fall out of the head.

Spent more time last night boiling it, trying to pick any residue out of the mechanism, etc etc.

How tightly do clog prufs hold the blade? Is there supposed to be zero play, or do they rattle ever so slightly? The top cover closes, but I can wiggle it a few millimeters - when the blade is in, it causes the blade to move ever so slightly as well. I shaved part of my hand with it and didn't cut myself, but it makes me a bit nervous to go at my neck with it like that.

Also, any other suggestions as to how I can get it super clean? Thought about soaking it in something, but I'm not sure what would dissolve the gunk inside it without harming the finish. Although, I'm not too concerned about the finish - it already has some brassing in places.

Thanks gentlemen.